Electrical apparatus



April 12, 1927. 1,624,314

T. w. CASE ELECTRICAL APPARATUS Filed Jan. 25. 1923 Patented Apr. 12, 1927.

UNITED STATES ELECTRICAL APPARATUS.

Application filed January 26, 1823. Serial No. 614,762.

This invention relates to a new and improved electrical apparatus particularly adapted for translating sound Waves into light waves, or variations of light waves 1 which can be efliciently photographed or reproduced upon a film, thereby constituting a translatable film record of sound waves, particularly articulate or musical sound waves.

I have produced, and my invention includes as a separable element, an instantaneous varying actinic light source of a most eificient character, particularly applicable to the production of a clear, distinct and readily translatable photograph of electrical variations, especially as effected by variations in sound waves. The main object of the invention is the production of an improved apparatus of great sensitivity to sound vanations, and from which a new, novel and translatable film record can be made, and the invention includes as the esential element a stable source of concentrated light approaching as close as is practical to a po1nt of light which can be varied in accordance with sound waves, and is highl effective for photographing through the comparatively minute area of a camera slit or opening, past which the photographic film moves.

The very essentials of my invention are two electrodes arranged in very close roximity and surrounded by an easily ionlzable gas, such as preferably helium, which gives a highly actinic light for photographic purposgs, altho argon may be satisfactorily use My invention has the further advantage that it permits the insulation of the negative electrode, or the covering of portions of the negative electrode with insulating material so as to confine the negative glow to the area desired which when a lens is to be used should be very small rather than difi'used over a large area.

The tube or sound reactive lamp of m invention does not require the use of a hig voltage high frequency current, but is operated as hereinafter described by direct current of com aratively low voltage. The operation can be carried on satisfactorily with a voltage on the lamp of from 200'to 400 volts, the reguired voltage varying somewhat in accor ance with the pressure he gas within the tube.

Other objects and advantages relate to the detalls of form, and construction of the apparatus, all as will more fully appear rom the following description, taken in connection with t e accompanying drawmgs, in which lgure 1 is a diagrammatic illustration of an embodiment of my invention.

lgure 2 is a diagrammatic illustration of a further embodiment of m invention.

' illustration of nected 1n circuit with a source as the battery -2- and with th of a transformer 4-, the secondar -5- of which is connected in circuit with the filament -6- and the grid 7 of an electron-discharge device 8, the plate 9 of which is connected in circuit with the filament -6-, such circuit including a source of potential, as the battery 10 and a primary 11- of a transformer trodes -14- and -15 of the sound wave reactive lamp l6 such circuit preferably including a source of potential -17- for maintainin a continuous discharge between the electrodes 14 and 15. i The bulb of the lamp -16 is filled with an easily ionizable gas, preferably helium, which gives a highly actinic light for photographic purposes and the electrodes --14 an are arranged in close proximity to each other, whereby a highl concentrated and comparatively small light is produced peculiarly adapted for photographic purposes in connection with the usual camera which embodies a very narrow slit or opening -23 for the passage of the light to the moving film -18.

Further concentration may be effected by of a concentrating lens 100 the interposition 19 as illustrated. The very essential of proximity of the trode -22- may be a wire which terminates referably adjacent the lower end of the c inder and is positioned substantially axial y of the cylinder, and in this construction of apparatus, the c lindrical electrode 21 is negative and the electrode -22- is positive, whereby the negative glow is concentrated within the cylindrical electrode in a manner quite advantageous for photographic purposes.

When referring in the specification and claims of this a plication to the electrodes being arranged in close proximity, I mean that the electrodes are spaced apart a distance not greater than one-quarter of an inch, and preferably not greater than oneeighth of an inch, and for the purpose of accomplishing the construction illustrated in Figure 2, the cylindrical electrode -21-- may perhaps preferably be approximately three-eighths of an inch in diameter.-

As above stated, the light produced at the lamp --16- is comparatively small and highly concentrated, and is produced by a direct current of comparatively low voltage and is highly sensitive to variations in electric current as eflected by-variations in sound waves acting upon the microphone "1- 2 1 The filament -6- may be heated in any suitable manner as by a heating circuit including a source of potential -24--. In Figure 3 a further form of my invention 1s illustrated, and in the hook-up shown, the

transformer --12-- is omitted and the lamp 25'- is inserted in the circuit between the filament -6- and the plate -9- inplace of the primary -11- of the said transformer.

It is found that this hook-up operates in an efficient mannerwhen a current of about 350 volts is applied to the circuit and the battery -10 should be adapted for that purpose. The lamp --25- is of slightly different construction than that shown in Figure 2, the electrode --26-- being in the form of a comparatively small wire ring, and the electrode 27- may be constituted of the end of the conductor or wire which penetrates the base of the lamp bulb and this wire or electrode projects but a short distance within the lamp, and relatively small for the pur ose ing a concentrated light '0 comparatively small area. For illustration, the electrode -27- may project one-eighthof an inch within the lampand should be of as small diameter as is practical, and is preferably th to th of an inch from the ring 26-. Obviously, however, I do not desire to limit myself to the exact length of projection of the electrode or its exact diameter with the understanding that I am describing a preferred form. The electrode -27 is the negative electrode in the strucis, therefore," of produc ture of Figure 3' for the reason that in this appiratus a concentrated negative glow is use I have further discovered that if the electrode which is to be used as the negative electrode be coated with an alkaline earth oxide such as calcium, barium or strontium, or have the oxides or oxide, or the volatization product of such oxides, deposited thereon or if the electrode be formed of or include a radio-active material, the voltage at which the lamp ma be operated is very materially reduced, and once started the bulb will carry a much greater current, and the subject matter of that discovery is being made the basis of a separate application.

Altho the structure of Figure 3 operates in a satisfactory manner, yet the interposition of the transformer. -12- as illustrated in Figures 1 and 2 has in my present opinion, certain advantages, particularly when the secondary 13- is of low resistance (as for instance 120 ohms) when compared with the primary 11-.

In the apparatus illustrated in the drawings, there is shown a single step of amplification which embodies an electron discharge tube -8-- and suitable circuit connections. It will be obvious that other steps of amplification may be inserted in the apparatus should that be desirable, and that where the same is-not required or desirable, the electron discharge tube -8 and its circuits may be omitted and the secondary 13-- of the transformer -12- be utilized as the secondary of the transformer -4-- in'place of the secondary -5--illustrated in the drawings.

By the use of the expression an easily ionizable gas, as used in the specification and claims hereof, I do not mean to limit myself to one particular kind of gas, but rather use the expression as illustrative of any easilyv ionizable gas, whether it be gas of a single kind, or a combination or mixture of gases, as for instance, helium and argon.

Altho I have shown and described specific constructions ofv apparatus as illustrative of embodiments of my invention, I do not desire to limit myself to the details of form, construction orarrangement, or to the use of any particular gas within the lamp 16-- so long as it be an easily ionizable gas, except where the said particular elements and details are specifically set forth in the claims hereto appended.

I claim: a j 1. In an apparatus for producing a photographic record of light wave variations corresponding to electrical variations, a bulb containing a pair of electrodes spaced apart a distance not substantially greater than one-eighth of an inch, and a gas within the bulb at such a pressure that a' concentrated containing a pair glow is produced about the negative electrode separate from the anode glow at an operating voltage not substantially greater than 400 volts direct current.

2. In an ap aratus for producing a photographic record of light wave variations corresponding to electrical variations, a bulb containing a pair of electrodes spaced apart a distance not substantially greater than oneeighth of an inch, and helium within the bulb at such a pressure that a concentrated glow is produced about the negative electrode separate from the anode glow at an I operating voltage not substantially greater than 400 volts direct current.

3. In an apparatus for producing a photographic record of light wave variations corresponding to electrical variations, a bulb of spaced electrodes, and

a gas within the bulb at such a pressure that a concentrated glow is produced about the negative electrode separate from the anode glow at an operating voltage not substantially greater than 400 volts direct current.

producing a photorecord of light wave variations corresponding to electrical variations, a bulb containing a pair of s aced electrodes, and helium within the bulb at such a pressure t at a concentrated glow is produced about t e negative electrode separate from the anode glow at an operating voltage not sub stantially greater than 400 volts direct current.

In witness whereof I have hereunto set my hand this 17th day of January, 1923.

THEODORE WILLARD CASE. 

